1. Field of the Invention
This invention relates to a structure for mounting an angle sensor for detecting a fuel injection timing in a fuel-injection-type multicylinder engine mounted on a motorcycle.
2. Description of Background Art
The concept is currently known in which an angle sensor is supported by a valve driving camshaft of the multicylinder engine (see Japanese Patent Publication No. Sho 63-26267).
Generally, assuming that a fuel-injection-type engine is carried on a motorcycle, and an angle sensor for detecting a fuel injection timing of the engine is mounted on a valve driving camshaft, the following are required:
The angle sensor would operate accurately all the time.
It would be easy to mount the angle sensor on the engine with precision.
Easy maintenance of the angle sensor would be possible after mounting of the angle sensor on the engine.
The angle sensor can be seen well from outside.
With the angle sensor mounted on the engine, it would be unnecessary to make any structural design change over any existing elements such as the frame.
The angle sensor would not interfere with any obstruction.
The angle sensor would be kept from being smeared with rain, splashes, dirt, etc. With the angle sensor mounted on the engine, any projection would not appear on the engine.
It is therefore an object of this invention to provide a novel structure for mounting an angle sensor of a multicylinder engine in a motorcycle in such a manner that as many of the above-itemized requirements are fulfilled as possible.
In order to attain the above-mentioned object, according to the present invention, there is provided a structure for mounting an angle sensor of a multicylinder engine in a motorcycle in which the multicylinder engine is horizontally suspended on a frame with one side surface opening to the outside as viewed in a side elevation, wherein the engine has on one transverse end of the frame a timing transmission chamber in which a timing transmission mechanism for transmitting rotation of a crankshaft to a valve driving camshaft is accommodated. An opening surface is covered with a timing transmission chamber cover which is fixed to one end of the valve driving camshaft. A pulsar rotor of the angle sensor is supported by a driven gear of the timing transmission mechanism and, on the other hand, a cam pulsar of the angle sensor is supported by the timing transmission chamber cover in confronting relation to the pulsar rotor and is exposed to outside of the frame as viewed in side elevation. With this arrangement, mounting of the angle sensor on the engine and maintenance of the mounted angle sensor can be facilitated without either making a structural design change to the frame or affecting the mounting of other elements on the frame and their layout.
Also in order to attain the above-mentioned object, according to the present invention, there is provided a structure wherein the multicylinder engine is a double overhead camshaft (DOHC) type having a cylinder head on which an intake-side valve driving camshaft and an exhaust-side valve camshaft are disposed rearwardly and forwardly, respectively, of the frame, and wherein the pulsar rotor of the angle sensor is fixed to the driven gear of the timing transmission mechanism, which gear is fixed to one end of the exhaust-side valve driving camshaft and, on the other hand, the cam pulsar of the angle sensor, which pulsar confronts the driven gear, is fixed to the timing transmission chamber cover and projects from the frame as viewed in a side elevation. With this claimed feature, in addition to the attainment of the same results that of the present invention, it is possible to mount the angle sensor on the exhaust-side valve camshaft without changing the existing position of the engine.
Also in order to attain the above-mentioned object, according to the present invention, there is provided an angle sensor mounting structure, wherein the cam pulsar of the angle sensor is disposed within a projected plane of the engine as viewed in a side elevation and inwardly of the frame as viewed in plan. With the present invention, it is possible to mount the angle sensor on the exhaust-side valve camshaft without changing the existing position of the engine.
Still also in order to attain the above-mentioned object, according to the present invention, wherein the cam pulsar of the angle sensor has a pulsar body fixed to a flattered pulsar cover, the pulsar body, being retracted into the timing transmission chamber via an attaching opening aperture of the timing transmission chamber cover and the pulsar cover being attached to an exterior surface of the timing transmission chamber cover. With this feature, the angle sensor can be mounted on the engine in such a manner that no projection would appear on the engine or that the entire engine would be increased in size or have it""s appearance impaired.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.